I came to the passage thinking ut = uti, and that the sentence described two results achieved by Dumnorix.

But then I began to wonder why Caesar would use both words in one sentence. Lewis’s Elementary Latin Dictionary led me to understand that ut = uti only in certain usages. Uti would not be used to introduce a result, but ut and uti would be synonyms when introducing a temporal clause (in which the verb would be in the indicative). At this point I noticed that “perficit” was indicative.

So now I think the passage means something like: “. . . that they would allow the Helvetii to go through their territories as soon as he brought about the exchange of hostages”

Is my understanding correct? I ask because I haven’t seen this (temporal) sense expressed in the translations I have read.

Here I think "quod" and "quia" are synonymous,—"because" in English,—varied for the same reason that, in English, if you repeat "because" it's confusing, so you vary with "in so far as" in the first or "for" in the second.Hâc in sententiâ, et quod et quia ut conjunctiones adhibentur, quae synonyma variantur ne clausulae mutuae confundantur.

"No one would set store in a fellow teaching in so far as they understand from the mouth of the one teaching, because unless the one teaching is within [the hearer], the teacher's tongue labours vainly on the outside."or // vel"No one would set store in a fellow teaching because they understand from the mouth of the one teaching, for unless the one teaching is within [the hearer], the teacher's tongue labours vainly on the outside."but not // sed non"No one would set store in a fellow teaching because they understand from the mouth of the one teaching, because unless the one teaching is within [the hearer], the teacher's tongue labours vainly on the outside."

Of course, if I'm wrong about the translation, my own tongue is operating in a vacuum.Postremò, si malè verto, lingua mea propria in vacuum laborat.

Thanks for staying with this adrianus. The translations you offer from St Gregory are all still pretty hard going, but I take your point that employing synonyms can help to make a sentence easier to comprehend.

But Caesar's use of two synonyms in one sentence was just the starting point for my reflection, which led me to conclude that:

" . . . obsidesque uti inter sese dent perficit"

was not a result clause, as perficit was indicative. That leads to quite a plausible translation:

“. . . that they would allow the Helvetii to go through their territories as soon as he brought about the exchange of hostages”